Electric-telegraph system.



C. ADAMS-RANDALL.

ELECTRIC TELEGRAPH SYSTEM.

APPLICATION FILED MAR. 6, 1916.

Patented Apr. 10, 1917.

2 SHEETS-SHEET I.

Moe/WW C. ADAMS-RANDALL.

ELECTRIC TELEGRAPH SYSTEM.

APPLICATION FILED MAR. 6. 191a.

Patented Apr. 10, 1917.

2 SHEETS-SHEET 2.

C/zarlesfldams fiandall,

Tl l T FTQ.

CHARLES ADAMS-RANDALL, 0F BUSTON, MASSACHUSETTS.

ELECTRIC-TELEGRAPH SYSTEM.

Application filed March 6, 1916.

To all 207mm z'tmay concern:

Be it known that I, CiIAnLns ADAMS- RANDALL, a citizen of the United States, re siding at Boston, in the county of Suffolk and State of Massachusetts, have invented certain new and useful Improvements in Electrio-Telegraph Systems; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will. enable others skilled in the art to which it appcrtains to make and use the same.

This invention relates to electric telegraphy and particularly to the employment therein of induced electric currents or impulses; to the novel and special arrangement of the main line and local circuits; and to the apparatus used in connection therewith; the invention being especially applicable to the manual transmission of messages over or upon the usual telegraph circuits.

The objects of the invention are, the cilicient transmission without repeaters over longer direct circuits than is now possible; to improve the sending or transmitting means; to improve and simplify the receiving in struments; and to reduce the expense of operating.

To these ends the invention consists generally in the novel arrangement of the main line circuit in combination with the local receiving circuit and the instruments used therewith both for sending and for receiving, as is particularly pointed out in the following description and claims, reference being bad to the accompanying drawings forming a part of the specification, in which:

Figure 1 is a diagrammatic illustration of the preferred arrangement of the circuits and apparatus;

Fig. 2 is a view similar to Fig. 1 showing a slightly modified arrangement of apparat-us;

Figs. 8, 4 and 5 are diagrammatic views illustrating still further modified arrangements of the circuits shown in Fig. 1;

Fig. 6 is a diagrammatic view showing the use of a tertiary wound compound coil; and

Fig. 7 is a diagrammatic view showing the arrangement of circuits between two terminal stations, with an intermediate station interposed between them.

In this invention the method employed may consist first, in the sub-division of the usual transmitting battery into separate batteries of comparatively low energy arranged.

Specification of Letters Patent.

Patented Apr. 10, 1917.

Serial No. 82,456.

in independent local circuits for transmitting instead of being inthe main line circuit; or, second, the main line battery may be split and one half of the same used at each terminal directly in the closed main line circuit; the opposite poles of the battery being connected to the ground at each terminal, with the transmitting keys connected in the main line as is now generally practised.

In the first case, the primary of an induction-coil is included in the local transmitting battery circuit together with a telegraph key for making and breaking the current passing over the closed local circuit, thereby inducing alternating currents in the secondary-coil of the induction-coil included in the main line circuit. These said induced currents become the main line current for actuating or controlling the action of the receiving instrument comprising an intermediate reproducing-coil. In this form of the invention the main line is always connected for use by any operator on the line without the necessity of keeping the transmitting circuit constantly closed. for the transmitting circuit need be closed only when in use, thereby saving the consumption of current when it is not in use.

It will be understood, however, that a closed circuit employing a gravity battery may be used if desired.

The intermediate reproducing-coil used in combination with the induction coil, consists of a compound wound coil, (or a plurality of such coils,) having one of its windings which I term the line coil connected in the line in series with the secondary winding of the induction coil; its other winding being connected at one terminal to a receiver terminal, while the other terminal of the last named winding is left open to the air and physically disconnected from the line or ground. The other terminal of the receiver connection may be either left open to the air, or connected to the line, or to the ground as may be determined by the differing line conditions.

The receiver used in this invention is preferably a magneto-electric instrument, such as the well known magneto-telephone, or a suitable polarized relay.

A suitable megaphoneor bell mouth is preferably attached to the receiver for augmenting the volume of sound or thequality of tone.

The receiver for general use is preferably non-adjustable, but it will be readily understood by those skilled in the art, that for some uses as for instance, on circuits where there is interference from induction, the receiver may be adjustable in the manners well known, and not illustrated, by simply adjusting the diaphragm or other vibrator out of the magnetic field as required, or, by adjusting the magnet away from the diaphragm or vibrator, thus making it less sensitive to the induction and overcoming its detrimental effects. Such desensitized receiver may be made operativeto the transmitted impulses by increasing the energy of the transmitting current, if found necessary or desirable.

The transmitting key preferably used in connection with this invention has its contact points reversed as compared to those of the usual telegraph key, whereby the circuit is closed by the upward movement of the key-lever and is broken by its downward movement, instead of being closed by the downward movement of the key-lever and broken by its upward movement, as is the case with the present telegraph key.

The advantages of this form of construc-' tion reside in the fact that the closing of the battery circuit is automatic and the contact is always made with the same uniform pres- I sure, thereby permitting the current-flow from the battery to be always uniform and at substantially its maximum force, while the breaking of the circuit is accomplished with a minimum amount of labor by the operator. On the other hand, under the present method and with the keys 'now employed, "the current-flow from the battery depends upon the pressure-contact made by the operator upon depressing the key-lever which contact, when thus made is variable espe-- I eially in rapid sending. The contact pressure varies wlth different operators and is not always positive and regular, with the result that the maximum energy from the bat tery' is not obtained at every closing. In

7 such cases it therefore necessarily follows r is broken than when it is closed.

,coil, whereby the receiver reproduces the dotsand dashes or other signals with a maximum eflicieney.

. The two W1I1Cll11gs of the reproducing coils should be simultaneously wound upon a soft iron core and should have approximately the same number of ampere-turns and the same resistance.

In the drawings F 1 illustrates the simplest form of the invention, in which the station A is provided with a battery 1, one pole of which is connected by the wire 2, to one end of the primary winding 3 of an induction coil 4. The other end of the primary 3 is joined by a wire 5 to a contact point 6 of a suitable telegraph key 7 which key is provided with the usual circuit breaking switch 8. This said switch 8 is, for the sake of clearness, illustrated in the drawings as being separate from the telegraph key 7 and is connected by the wire 9 to the other pole of the battery 1.

10 indicates the secondary winding of the induction coil 4:, one end of which is c011- nected by the wire 11 to the ground G, while its other end is connected by the wire 12 to one end of one winding 13 of a compoundwound coil 1%. The other end of the winding 13 is joined to the line wire 15, extending to the station B. The second winding 16, of the compound-wound coil 11, has one of its ends left disconnected or open to the atmosphere as at 17 while its other end is joined by a wire 18 to one terminal of a suitable receiving instrument 19, whose other terminal is grounded by a wire 20 joined to the wire 11, as will be clear from the drawings.

The receiving instrument 19 may be of any suitable type, but as above explained I prefer to use the ordinary magnetic telephone receiver, provided with a megaphone or other suitable sound magnifying device.

The apparatus and circuits at station B are similar in every respect to those just disclosed in connection with station A and comprise a battery 21, one side of which is joined by a wire 22 to one end of the primary winding 23 of an induction coil 24:, the other end of the said primary 23 being connected by a wire 25 to the contact point 26 of the telegraph key or other circuitbreaker 27, provided with the switch 28 joined by the wire 29 to the other side of the battery 21. One end of the secondary 30 of the induction coil 24 is grounded, as at G, bythe wire 31, while the other end of the said secondary 30 is connected by the wire 32 to one end of the winding 33 of the compound-wound coil 34, the other end of the said winding 33 being connected to the line wire 15. The other winding 36 of the compound wound coil 34 has one of its ends 37 physically disconnected, while its other end is joined by the wire 38 to one terminal of a receiving apparatus 39, whose other ter- .minal is grounded by the wire 40, connected to the wire 31.

The operation of the form of the invention just disclosed will be clear from the foregoing, but it may be briefly summarized as follows:

Upon the depression of the telegraph key or circuit breaker 7, current flowing from the battery 1 through the primary 3 of the induction coil 1 will be interrupted and a current will be induced in the secondary winding 10 of the said induction coil i. The said induced current may be said to travel from one side of the said winding 10 over the wire 12, winding 13 of compoundwound coil 14, main line wire 15, winding 33 of compound-wound coil wire 32, secondary 30 of induction coil 24, wire 31, ground G to ground G, and wire 11 back to the other side of the secondary 10.

The said induced current traversing the winding 33 of the coil 3 1 will induce a corresponding current in the winding 36 of the said coil 3a, which last mentioned current will traverse the wire 38, the coils of the receiving instrument 39, and wires 40 and 31 to ground G, thus reproducing at the station B a signal corresponding to that pro duced at key 7 of station A.

I have found by actual tests that the use of a compound-wound coil constructed and connected as above disclosed not only increases the clearness with which signals may be received at the receivers 19 and 39, but it also increases to a material extent the distance over which such signals may be transmitted without the use of relays, repeaters, or other intermediate retransmitting apparatus. I have also found this to be true, notwithstanding the fact that one of the terminals, such as 17 or 37, of one of the windings of each of the compound-wound coils is left physically disconnected or open to the atmosphere.

The arrangement shown in Fig. 2 is substantially the same as that disclosed in Fi 1, except that an additional compoundwound coil, such as is employed at the station A, while a similar coil 51 is used at station B. The coil 50 has one of its windings, such as 52, joined in the main line in series with the secondary winding 10 of the induction coil 4c and the winding 13 of the compound-wound coil 14, while its other winding 53 is connected in series with the winding 16 of the compound-wound coil 1 1. In like manner, the coil 51 has one of its windings, such as 5 1, joined in series in the main line with the secondary 30 and winding 33 ofcoil 34:, and its other winding 55 is connected in series with the winding 36 of the said coil 34.

The form of the invention shown in Fig. 3 only differs from that shown in Fig. 1 in that a rheostat or other suitable adjustable resistance, such as 56, is interposed in the main line between the secondary winding 10 of the induction coil 4 and the ground con nection G. I find the use of such a resistance desirable under certain conditions in order to force a greater portion of the induced currents from the winding 10 over the main line to the station E and ground when sending from the station A; and also to modify the volume or tone of the home receiver 19.

In Fig. 4 I have shown the receiver 19 as being connected in series in the main line with the winding 13 of the coil 1-1, while the secondary 10 is joined in series with the winding 16 of the said coil 1 1. Suitable switches such as and 61 are provided in the main line and secondary circuits, respectively, in order that the said circuits may be grounded or left open at will.

In Fig. 5 the receiver 19 is again shown connected directly in the main line, which also includes the winding 13 of the compound-wound coil 1 1, the end of the said winding being left disconnected. The other winding 16 of the coil 14: is joined in series with the secondary 10 of the induction coil 1 and is grounded through a rheostat or adj ustable resistance 65 and a suitable condenser 66. The use of the rheostat and condenser, as was above disclosed in connection with the rheostat shown in Fig. 3, forces the greater portion of the currents induced in the secondary 10 over the line wire 15 to the station B.

Fig. 6 shows a further modification in which the compound-wound coil 14 and the induction coil 1 are combined in the form of a tertiary wound coil 70, having the wind- 71, 72 and 73. The use of such a coil not only gives as good results as does the separate coils but also reduces the space necessary for the apparatus as well as cost of installation.

Fig. 7 shows a further modification illustrating two terminal stations A and B somewhat similar to those heretofore disclosed and an intermediate station C. In this arrangement the induction-coils 4i and 24. at the terminal stations are dispensed with and the telegraph keys as well as the transmitting battery are included directly in the main line circuit, a portion of the latter being located at each of the said terminal stations A and B.

The intermediate station C is provided with a compound-wound coil 75, having one of its windings 7 6 connected in the main line in series, its other winding 77 being joined at one end to the receiver 78, as shown, and having its other end left disconnected. The telegraph key 79 is included in a branch circuit and may be connected in the main line at will by the switch 80.

Under this arrangement the line circuit is constantly closed, similar to the present manually operated telegraph systems, and is normally connected for use at any of the stations. Further, the induction-coils are dispensed with, the breaking of the main line battery current at either of the keys in the main line causing the generation oi: currents of sufiicient energy-in the coils 16, 77

and 36 to actuate the receivers to reproduce the dots, dashes or other signals in an eiiilay, sounder or register and the local battery and circuits required therefor in the present manually operated telegraph system. lhe adjustable receiving instruments now in use being dispensed with, 'allrtroubles from adjusting are overcome and the cost of the local battery and the expense of maintainmg the same are saved.

The principle 01' operation of the invention is practically the same under the diflercut arrangements of circuits and apparatus shown in the drawings, the main diiference between the arrangements shown at Figs. 1 to 6 inclusive, and that of Fig. 7, being in the sub-division of the transmitting main line battery into a plurality of local transmitting batteries. 'By this means a further economy as well as more eiiicient operation is obtained, in that a less number of cells of battery are required when thus sub-divided, even with a large number of intermediate stations. 4 s

p Having thus describedmy invention, what I claim is I 1. In a telegraph system the combination of a 'main line circuit provided with stations; an induction coil and a compound wound reproducing coil at each 01" said stations, each of said coils having one of its windings included in said main line circuit; a local receiving circuit including a receiver and another winding of said compoundwound coil atreach station, said receiving circuit having one of its terminals open to the atmosphere; and a physically discon- "nected transmitting circuit including a bat- Gopiesof this patent may be obtained. for

another of the windings of said compoundwound coil, and having one of its terminals open to the air; and a second local circuit including the other winding of said induction coil, a battery and a telegraph key, substantially as described.

, 3. In a telegraph system the combination (if a main line circuit including a receiver and having one of its terminals open to the air; a compound-wound reproducing coil provided with a plurality of windings, one of which windings is included in said main line circuit; an induction coil; :1 local circuit including one of the windings of said induction coil and another of the windings of said compound-wound coil; a condenser and an adjustable resistance in said local circuit; and a second local circuit including the other winding of said induction coil. a battery and a telegraph key, substantially as described.

4. In a telegraph system the combination of a tertiary coil; a grounded main line circuit including one of the windings of said coil; a local transmitting circuit including another of the windings of said coil, a battery and a telegraph key; and a local receiving circuit including another winding of said coil and a receiver, and having one of its terminals open to the atmosphere, substantially as described.

In testimony whereof I aflix my signature,

in presence of two witnesses.

CHARLES ADAMSRANDALL.

lVitnesses CHAs. C. DASEY, A. M. SULLIVAN.

five cents each, by addressing the Commissioner of Patents.

' Washington, D. C. 

